1. Field of the Invention
The present invention relates to a silicone-modified wax-containing composition and a cosmetic preparation containing the composition. The composition is suitably in a past or slurry form at room temperature and can be blended in the cosmetic preparation without being melted at high temperatures.
2. Description of the Related Art
An oily thickening agent such as a wax or a gelling agent (hereinafter collectively referred to as the “thickening agent”) is used for the purpose of increasing a viscosity of oily components in a cosmetic preparation to improve a usability, a stability and an appearance of the cosmetic preparation. Here, the wax indicates broadly solid unctuous agents at room temperature. As the oily thickening agent, hydrocarbon-based waxes such as ceresin, polyethylene and ozokerite, natural waxes (i.e., wax esters) such as carnauba wax and candelilla wax, and polysaccharide fatty acid esters such as sucrose palmitic acid ester have been widely utilized.
These thickening agents are usually necessary to be melted at a temperature equal to or higher than a melting point of the thickening agent when blended in the cosmetic preparation. Therefore, when a thickening agent having a high melting point is blended, other components in the cosmetic preparation may be deteriorated or decomposed. Thus, it is desired that the melting point is low and particularly lower than 100° C. However, a thickening agent having a low melting point generally has a low thickening effect, and decrease in the viscosity or a phase separation of the cosmetic preparation may occur in some cases in a summer season. From these points, the melting point of a thickening agent is preferably about 60 to 95° C.
It is also desired that the thickening agent has a good compatibility with a low-viscosity unctuous agent that is blended in the cosmetic preparation. If the compatibility is poor, the thickening agent is separated from the unctuous agent with time, or crystals of the thickening agent become large when the cosmetic preparation is cooled, to impair the appearance and a feel of the cosmetic preparation in some cases. Further, it is desired that the thickening agent matches with other thickening agents well. If they do not match well, one thickening agent may inhibit the thickening effect of other thickening agents.
A silicone oil has been frequently used as an unctuous agent for cosmetic preparations because it has excellent properties, e.g., it has a non-viscous feel, its spread is good and its water-repellent property is good. Among them, a silicone oil having a low viscosity is frequently used for composing cosmetic preparations having a light feel and no greasy feeling. However, the silicone oil has a poor compatibility with common unctuous agents, does not match with thickening agents, and easily causes the above problems. The silicone oil also has the problem that the silicone oil has a good flatting property, excessively spreads when applied on the skin and thus can not form a cosmetic film having a thickness which gives a fatted adhesive feeling.
In order to solve the above problems, thickening agents which can thicken the silicone oil having a low viscosity have been developed (Patent Documents 1 to 3). However, it is difficult for any of them to smoothly thicken the silicone oil alone, and a resulting thickened one lacks a smoothness required for cosmetic preparations. Thus, a silicone-modified olefin-based wax has been proposed for solving these problems (Patent Document 4)    Patent Document 1: EP 0357037 A2    Patent Document 2: US 2004/0071741 A1    Patent Document 3: JP 2-132141 A    Patent Document 4: JP 2008-174571 A